Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D11/00—Clutches in which the members have interengaging parts
  • F16D11/14—Clutches in which the members have interengaging parts with clutching members movable only axially
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D23/00—Details of mechanically-actuated clutches not specific for one distinct type
  • F16D23/02—Arrangements for synchronisation, also for power-operated clutches
  • F16D23/04—Arrangements for synchronisation, also for power-operated clutches with an additional friction clutch
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D11/00—Clutches in which the members have interengaging parts
  • F16D2011/002—Clutches in which the members have interengaging parts using an external and axially slidable sleeve for coupling the teeth of both coupling components together

Definitions

• the present invention generally relates to shaft coupling systems, making it possible to transmit a torque from one shaft to another, and in particular to speed reduction systems with two gear ratios.
• a shaft coupling device comprising:
• the invention also relates to a speed reducer comprising a shaft coupling device as mentioned above, and a motor vehicle equipped with such a reduction gear.
• An internal combustion engine develops a torque which varies with the rotation speed of the crankshaft. Such a motor therefore has a restricted range of use. In a motor vehicle equipped with such an engine, it is then necessary to associate a gearbox with the engine.
• gearbox systems In this field, numerous gearbox systems have been developed. Generally, such a box comprises two shafts provided with facing pinions of different diameters which mesh with each other, the pinions of one of the shafts being for example mounted loosely on this shaft (i.e. i.e. being left free to rotate on this shaft) while the others are fixedly mounted on the other shaft. In order to change a gear ratio, these gearboxes use coupling devices designed to couple one of the idler gears with the gearbox shaft on which it is mounted so as to equalize their rotational speeds.
• the coupling devices generally comprise a slider which is linked in rotation to one of the shafts of the box and which is adapted to slide on this shaft to come, by means of fingers, to engage a toothing of an idler gear.
• the electric machine is coupled to a speed reducer.
• this gearbox is single-ratio. He A gearbox is therefore generally not provided.
• An electric machine is in fact adapted to deliver a substantially constant torque over a wide range of rotational speeds. It can therefore be used with such a reduction gear in a motor vehicle.
• the advantage of a single-speed gearbox is that it is simple, inexpensive, and does not pose a problem of torque loss (when changing gear ratios).
• the present invention proposes a two-speed gearbox, of simple architecture and capable of causing almost no torque break during a gear change. speeds.
• the coupling system comprises:
• a selection slider mounted sliding relative to the hub along said main axis between a position coupled to one of the idler gears and a position coupled to the other of the idler gears
• a locking slider mounted sliding relative to the hub along said main axis between a position coupled to one of the idler gears and a position coupled to the other of the idler gears
• the elastic return means which are adapted to return the locking slider to a position coupled to the same idler gear as the selection slider.
• the selection player therefore allows, thanks to the displacement member, to change a gear ratio when it is moved from one coupled position to another.
• the locking slider allows each gear ratio to be locked.
• the elastic return means allow, during a gear change, to let the selection slider move to its position coupled to the new idler gear even if the locking slider was hindered in its movement by this other idler gear (or vice versa).
• this architecture will make it possible to place the two players in a neutral position, between the two idler gears, so that they are not coupled to any of these idler gears.
• This neutral position can be used in different ways. It could for example be used to, during a gear change, synchronize the angular speeds of the sliding gears with that of the idler gear to be engaged. It can also be used, in a hybrid vehicle, to no longer drive the electric machine during phases where it is preferable for the vehicle's traction to be achieved solely by the internal combustion engine.
• each idler gear has at least one clutch facing the other idler gear
• the selection slider and the locking slider include fingers adapted to engage the clutches of the idler gears so that, when the selection slider and the locking slider are in the position coupled to the same one of said idle gears, their fingers take each dog of said idler gear in sandwich;
• the fingers of the selection slider and the locking slider having a first end turned towards one of the idler gears and a second end turned towards the other of the idler gears, the distance measured along the main axis separating the two ends of each finger is strictly less than the distance separating the clutches of one of the idler gears from the other of the idler gears;
• a computer which is programmed to control said member in three stable positions, including a first position in which the selection switch is in the position coupled to one of the idler gears, a second position in which the selection switch is coupled to the other of the idle gears, and a third intermediate position in which the selection slider is not coupled to any of the idle gears;
• each idler gear has a number of dogs regularly distributed around the main axis which is greater than or equal to two;
• the selection slider and the locking slider have an identical number of fingers regularly distributed around the main axis;
• the angular space around the main axis delimited between two clutches is strictly greater than twice the angular space around the main axis occupied by a finger of the selection slider;
• the hub has several recessed notches in its external face and distributed around the main axis, adapted to guide the sliding of the fingers of the selection slider and the locking slider;
• the locking slider is located inside the selection slider, between two stops of the selection slider, and the elastic return means comprise elements interposed between each stop and the selection slider;
• said elements are springs, preferably three or more pairs in number, each pair of springs comprising a compressed spring between one of the stops and the selection slider and a compressed spring between the other of the stops and the selection slider selection;
• each idler gear has a ramp and the locking slider has at least two ramps respectively adapted to slide against the ramps of a first of the idler gears after the selection slider has been moved to the position coupled to this first idler gear.
• the invention also proposes a speed reducer comprising a primary shaft which carries fixed gears and a coupling device as mentioned above whose idle gears mesh with said fixed gears.
• the invention also proposes a motor vehicle comprising an electric machine, a differential, drive wheels coupled to the differential and, between the electric machine and the differential, a speed reducer as mentioned above, including one of the primary shafts and main is coupled to the electric machine and the other of the primary and main shafts is coupled to the differential.
• FIG. 1 is a schematic perspective view of a speed reducer comprising a shaft coupling device according to the invention
• FIG. 2 is a schematic exploded perspective view of the interconnection system of the coupling device of Figure 1;
• FIG. 3 is a schematic exploded perspective view of one of the idler gears and the selection switch of the coupling device of Figure 1;
• FIG. 4 is a schematic view showing from different angles the two idler gears and the interconnection system of the coupling device of Figure 1;
• FIG. 5 is a schematic sectional view representing a clutch of a first idler gear, the clutch system and the second idler gear of the coupling device of Figure 1, seen from a first angle, when the first idler gear is engaged;
• FIG. 6 is a schematic sectional view representing the first idler gear, the clutch system and the second idler gear of the coupling device of Figure 1, in the neutral position when none of the idler gears are engaged;
• FIG. 7 is a schematic view representing the first idler gear, the interconnection system and the dogs of the second idler gear of the coupling device of Figure 1, seen from a second angle, during a change of gear ratio;
• FIG. 8 is a schematic view similar to that of Figure 7, at the end of the gear ratio change.
• Coupled will be used to designate a connection between two elements which makes it possible to transmit a torque from one of these elements to the other.
• FIG. 1 there is shown a dual-ratio speed reducer 1 with three stable positions, including two positions with engaged gear and a neutral position.
• “Stable position” means a position in which the speed reducer 1 can remain for an extended period (for example greater than a second), according to a control instruction imposed on it.
• This speed reducer 1 is qualified as a two-ratio in the sense that it makes it possible to offer exactly two speed reduction ratios, which is perfect for use in a motor vehicle.
• This speed reducer 1 is preferably intended to be installed in a motor vehicle, but it could be used in other fields (robotics, aviation, etc.).
• an electric machine hereinafter called an electric motor although it could be used as an alternator
• - wheels typically four in number and two of which are for example driving, and
• the speed reducer 1 is then placed between the electric motor and the differential 30 in order to be able to transmit the engine torque to the wheels (or vice versa).
• this speed reducer 1 has two stages of shafts housed in the housing. It thus comprises a primary shaft 10 which is coupled to the shaft of the electric motor, and a main shaft 21 which is coupled to the differential 30 (the reverse would also be possible).
• the primary shaft 10 is preferably directly coupled to the shaft of the electric motor.
• a torque limiter or a clutch could be interposed between these two shafts in order to facilitate gear shifting.
• the primary shaft 10 carries two fixed gears 12, 13, that is to say two gears which always rotate at the same speed as that of the primary shaft. These two fixed gears 12, 13 have different diameters to offer distinct speed ratios.
• the main shaft 21 extends along a main axis A1 parallel to the axis of the primary shaft 10. It is therefore engaged at its two ends in bearings 29.
• This main shaft 21 carries two idler gears 22, 23 which respectively mesh with the two fixed gears 12, 13. These gears are described as idler in the sense that they are mounted free to rotate on this shaft around the axis main A1 and that they are blocked in translation along this axis.
• this main shaft 21 also carries a fixed pinion meshed with a pinion of the differential 30.
• a system of interconnection 50 of the idler gears 22,23 is provided.
• This interconnection system 50 makes it possible to couple one or the other of the idler gears with the main shaft 21, depending on the gear ratio engaged. It also allows, in the neutral position, to leave the idler gears free to rotate around the main shaft 21.
• This interconnection system 50 which is more precisely the subject of the present invention, comprises four main components illustrated in Figure 2.
• selection player 520 is made in two assembled one-piece parts, while the other components are each made in one single piece. All of these components are, for example, made of hardened steel.
• the hub 540 comes from formation with the main shaft 21.
• the hub 540 is an independent part of the main shaft 21. It then has a central opening through which it is slipped onto this shaft, the edge of which has grooves or serrations engaged in reliefs provided in correspondence on the main shaft 21 in order to permanently couple this hub 540 to the main shaft 21.
• the two selection sliders 520 and locking 530 are then mounted relative to the hub 540 so as to be movable in translation along the main axis A1 but blocked in rotation around this axis. They thus make it possible to engage one or the other of the idler gears 22, 23 so as to couple this idler gear to the main shaft 21.
• each idler gear 22, 23 each conventionally comprise a main disc 225, 235 which has a central opening, here bordered by a crown, for its mounting on the main shaft 21 and which is bordered externally by teeth allowing its gearing with one of the fixed gears 12, 13.
• each idler gear 22, 23 comprises at least one clutch 220, 230, that is to say a relief which here projects from one of the faces of the main disk 225, 235 (the one facing the other idler gear) and by which the idler gear can be rotated.
• each clutch 220, 230 extends over a restricted angular sector of approximately 30° and has substantially the shape of a prism whose base is located on the aforementioned face of the main disk 225, 235.
• Each clutch presents thus four lateral faces and one end face turned towards the other idler gear.
• the internal side face (located on the side of the main axis A1) is here curved around this axis, and the same is true of the external side face.
• the two other lateral faces (hereinafter called radial faces) each extend at least partly in a radial plane (that is to say in a plane containing the main axis A1).
• the main face is connected to most of the side faces by fillets. However, it is connected to only one of the two radial faces by an inclined flat forming a ramp 231, the function of which will become clear below.
• ramps 221, 231 of the three clutches 220, 230 of each idler gear 22, 23 are oriented in the same direction around the main axis A1, and that this direction is opposite to the direction in which the ramps of the clutches of the other idler gear are oriented.
• ramps 221, 231 extend over only part of the thickness of the dogs 220, 230.
• the selection slider 520 and the locking slider 530 both have annular shapes such that they can be fitted into each other (the selection slider 520 being located at outside of the locking slider 530).
• the locking slider 530 thus comprises an annular body 533 whose internal diameter is adjusted to the external diameter of the hub 540 so that it can slide freely on the latter, parallel to the main axis A1.
• the selection slider 520 comprises an annular body 523 whose interior diameter is adjusted to the exterior diameter of the annular body 533 of the locking slider 530 so that it can slide freely on the latter, parallel to the main axis A1.
• the locking slider 530 then has a smooth cylindrical rotating external face.
• the hub 540 has a notched shape called “tulip”.
• the hub 540 has an exterior face which is not cylindrical but which has several recesses, here identical, regularly distributed around the main axis A1. These recesses therefore form notches 541 thanks to which the two players are blocked in rotation.
• Each notch 541 is profiled in the sense that its cross section (that is to say its section in a plane orthogonal to the main axis A1) is uniform along the main axis A1.
• This cross section here has a U shape, so that each notch has a flat bottom bordered by two flat side faces extending in radial planes.
• Six identical notches 541 are provided here.
• the locking slider 530 correspondingly comprises at least one finger adapted to slide in one of the notches 541.
• it comprises exactly three which are regularly distributed around the main axis A1 and whose cross sections are uniform and have identical shapes, in negative, to those of the notches 541.
• These fingers 531 are fixed on the internal face of the annular body 533 of this player. They thus have radial faces which slide against the radial faces of the notches 541 to block any rotational movement of this player relative to the hub 540.
• the selection player 520 includes at least one finger adapted to slide in one of the notches 541 delimited by the hub 540.
• it comprises exactly three which are regularly distributed around the main axis A1 and whose cross sections are uniform and have identical shapes, in negative, to those of notches 541.
• the selection player 520 comprises, at one end, a rim 527 projecting from its internal face which extends over at least part of its periphery.
• this rim 527 is interrupted in three places by passage notches for the fingers 531 of the locking slider 530.
• the fingers 521 of the selection slider 520 extend at a distance from the internal face of the annular body 523 of this slider, which we recall slides along the face external of the annular body 533 of the other player.
• these fingers 521 are connected to the annular body 523 by one of their ends only, via the rim 527.
• the annular body 533 of the locking slider 530 can slide between the annular body 523 of the selection slider 520 and the fingers 521 of the latter.
• the fingers 521 have radial faces which slide against the radial faces of the notches 541 to block any rotational movement of this player relative to the hub 540.
• Elastic return means are then provided to return the latter to the same height as the selection slider 520 along the main axis A1, so that when these return means are at rest, the ends of the fingers 521 , 531 of the two players extend at the same height, along the main axis A1.
• these elastic return means are presented here in the form of three pairs of springs 550, 551 distributed at the level of the three fingers 521 of the selection slider 520.
• each pair of springs comprises a first spring 550 which is interposed between one side of the annular body 533 of the locking slider 530 and a stop formed by the selection slider 520, and a second spring 551 which is interposed between the other side of the annular body 533 of the locking slider 530 and another stop formed by the selection slider 520.
• One of these stops is formed by the rim 527, which we recall connects the fingers 521 to the annular body 523 of the selection slider 520.
• the selection slider 520 is in fact made in two separate and assembled single-piece parts, namely:
• This other stop is presented here in the form of an annular flange 526, which is fixed rigidly and immovable on the assembly (for example by welding), after having put in place the springs 550, 551 and fitted the locking player 530 in the selection player 520.
• This flange 526 has in practice a shape similar to that of the rim 527. [0079] It will be noted in Figure 5 that this flange 526 has notches so as not to form an obstacle to the passage of the fingers 531 of the locking slider 530.
• the two sliders are therefore free to slide between the idler gears 22, 23, between two extreme positions, namely a position coupled to a first of the idler gears, and a position coupled to the other of the idler gears.
• the first idler gear 23 will designate for example the one allowing a first speed ratio to be established, while the second idler gear 22 will designate the one allowing a second speed ratio to be established.
• each finger 521, 531 (that facing the side of the first idler gear 23) extends at a distance from the second end of this finger which is less than the distance separating the end faces of the two clutches 220, 230, so that a single sliding gear cannot simultaneously engage the two idle gears 22, 23. In practice, this distance is substantially equal to the thickness of the hub 540 (along the main axis A1). [0086] It is therefore necessary to move it to shift into a gear ratio.
• the selection slider 520 is designed to be moved from one coupled position to the other by means of the selection member 510.
• this selection member 510 here comprises a single fork which is engaged in a groove 528 delimited by two peripheral ribs provided projecting from the external face of the selection player 520.
• the locking player 530 is not ordered. No fork is therefore associated with it. It is designed to move automatically and mechanically from a position coupled to any one of the idler gears to a position coupled to the other idler gear thanks to the movement of the selection slider 520, thanks to the springs 550, 551.
• the end faces 534 of the fingers 531 of this locking slider 530 extend in planes which are not orthogonal to the axis of rotation A1 but which are inclined relative to it, in order to form ramps of slopes conjugate with the slopes of the ramps 221, 231 of the dogs.
• the angle of inclination of a slope relative to a plane orthogonal to the main axis A1 is preferably between 5 and 45 degrees. It is 20 degrees here.
• the two end faces 534 of each finger 531 extend here in parallel planes.
• end faces of the fingers 521 of the selection slider 520 extend in planes which are orthogonal to the main axis A1.
• the speed reducer also includes an actuator for sliding the selection member 510 and a computer for controlling this actuator.
• This calculator includes for example a processor, a memory and different input and output interfaces. Thanks to its input interfaces, the computer is adapted to receive data such as for example the rotational speed of the electric motor and the torque delivered. Thanks to its output interfaces, the computer is adapted to control the actuator of the selection member 510. Thanks to its memory, the computer memorizes a computer application, consisting of computer programs comprising instructions whose execution by the processor allows the computer to implement the method described below.
• this idler gear 22 rotates at a speed different from that of the first pinion. idler 23, due to the fact that these two idler gears mesh with fixed gears 12, 13 of different diameters. In this case, this second idler gear 22 rotates faster than the first idler gear 23.
• the selection member 510 slides the selection slider 520 from its position coupled to the first idler gear 23 (figure 5) towards an intermediate neutral position in which it is not coupled to any of the idler gears 22, 23 (figure 6).
• the locking slider 530 is also driven towards an intermediate neutral position, in which it is not coupled to any of the idler gears 22, 23. Due to the friction between its fingers 531 and the clutches of the first idler gear 23, this movement may be slower. This movement can be helped by reducing the torque exerted by the electric motor.
• the fingers 521, 531 of the two sliders are at the same height and are therefore not resting against any of the clutches 220, 230 of the idler gears.
• the players are here preferentially maintained a few hundredths of seconds in this neutral position by the computer, so as to be able to slow down the electric motor and therefore, therefore, the rotation speed of the second idler gear 22.
• the objective is that at the end of this step, the second pinion always turns faster than the selection player 520 but the speed difference between these two elements has decreased, for example at least by half.
• the computer controls the selection member 510 so that it continues its movement in order to slide the selection slider 520 from this intermediate neutral position towards the position coupled to the second idler gear 22 ( figure 7).
• the selection slider 520 always turns less quickly than the second idler gear 22. But thanks to the significant angular spacing between two successive dogs 220, the second ends of its fingers 521 can slide into the space left between two dogs. The speed of movement of the selection member 510 is then fast enough for the interconnection to take place quickly.
• the first solution would be to control the change of gear ratio at the appropriate time, that is to say when the clutches are angularly offset relative to the fingers of the selection switch.
• the output of the actuator is here fixed to a U-shaped bracket 41 whose two arch-shaped arms overlap a selection shaft 42 which is fixed to the fork forming a selection member 510.
• This selection shaft 42 comprises a central part of reduced section, at the level of which slides 43 are mounted movable in translation, between the two arms of the stirrup 41. These two slides 43 are kept at a distance from one of the other by a spring 44.
• the present invention is in no way limited to the embodiment described and represented, but those skilled in the art will be able to make any variation conforming to the invention.
• the passage of a speed ratio is carried out without synchronization, but it nevertheless requires braking or accelerating the electric motor when the shifters are in the neutral position so that the shock to the time of interconnection is as limited as possible.
• the electric motor and the speed reducer described above could be installed in a hybrid vehicle, also comprising an internal combustion engine.
• the neutral position offered by the speed reducer could be used to decouple the electric motor from the internal combustion engine, when it is desired for the vehicle to be powered solely by the internal combustion engine.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Structure Of Transmissions (AREA)

Applications Claiming Priority (3)

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ID=86692707

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• 2023
  • 2023-05-17 CN CN202380054766.5A patent/CN119677969A/zh active Pending
  • 2023-05-17 EP EP23728656.2A patent/EP4544201A1/de active Pending
  • 2023-05-17 WO PCT/EP2023/063302 patent/WO2023222782A1/fr not_active Ceased

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